Serena Williams stands on the verge of securing the third part of a calendar Grand Slam at Wimbledon as she prepares to face Garbine Muguruza in Saturday's final.

Not since Steffi Graf in 1988 has a woman won all four major tournaments in a single year - Margaret Court the only other player to achieve that feat in the Open era.

Williams has, of course, held all four titles at once in the past - clinching the 'Serena Slam' by triumphing at the 2003 Australian Open - and would repeat that achievement with victory in her 25th grand slam final.

Only Court and Graf can better Williams' record of 20 grand slam crowns, but a win over Muguruza at the All England Club would see her close within one of the latter.

Williams has claimed the Wimbledon title on five previous occasions, including three of the last six years, but is taking a relaxed approach to her latest Centre Court decider.

"I've been in this stage [before]," she said. "I've won so many grand slam titles. And, you know, I'm at a position where I don't need to win another Wimbledon. I could lose tomorrow.

"Sure, I won't be happy. But I don't need another Wimbledon title. I don't need another US Open. I don't need any titles to make it.

"Every time I step out on court, the practice court, the match court, I do look at it as a more fun time because it's not as stressful as it was."

She meets impressive Spaniard Muguruza in the showpiece having only faced her on three previous occasions, including a surprise defeat at the French Open in 2014.

Williams described that defeat as "eye-opening" and credits it with making improvements to her game that have seen her return to the summit of women's tennis.

Her 35 wins and one defeat this year illustrate what a daunting task lies ahead for Muguruza, but the undoubted underdog is also full of confidence as she enjoys a dramatic upturn in form on grass.

In 2015, the 21-year-old has earned more wins on the surface than at any other time in her career and now she is ready to take down one of her idols.

"She [Williams] was kind of like an inspiration for me because when I was watching the TV, I would see her play finals and she was number one," she said ahead of her maiden grand slam final.

"It's weird. When I was eight, I was dreaming [of playing Williams in the final]. Now 11 years after, it's happening. It's amazing.

"But, you know, it's what I've worked for. It's the best. Now I'm feeling that all my effort, all the work that I did before, it's like paying off.

"She's world number one for a reason. She shows every year that she's the number one. She's the toughest player. It's going to be the hardest challenge tomorrow, [but] I'm going to enjoy tomorrow

"It is going to be the best day of my tennis career. If I win it is going to be much better."